Hanging on to what you're carrying is a natural instinct. That's why you need to plan to either drop it, chuck it at him, or work around it. Whenever you pick up anything, you should take a moment to think. "Is this a weapon, a projectile, or a hindrance?" Based on the answer, remind yourself what you would do with it if a situation arose (i.e. use it as a weapon, chuck it at him as a distrction, or either protect it or drop it as appropriate).
Like awareness, these pop quizzes are work, but they are well worth the effort.
Stay safe,
Mike